Gas-air mixer



March 19, 1957 J. F. LovETT GAS-AIR MIXER Filed March 24, 1955 lll11111111111111111111III/l 4 l Ill/lll fllll'lllllllllllll/I/IIIIA Vllllllllll( INVENTOR. JOSEPH E LOVETT ATTORNEYS United States Patent C GAS-AIR MIXER Joseph F. Lovett, Northfield, N. J., assignor to Archie R. Ammons, Millville, N. J.

Application March 24, 1955, Serial No. 496,530

1 Claim. (Cl. 158-118) This invention relates to improvements in gas mixers and more particularly to an improved device for mixing combustible gaseous materials, such as natural gas or the like, with air.

in order to insure proper burning of natural gas and other high B. t. u. gases, it is essential that the gas be intimately intermixed with air before it is tired. The known mixers in use today capable of obtaining a proper combustible mixture of natural gas and air, such as pre-mixer devices and the like, are often prohibitive in cost whereas those of lesser cost, such as venturi-type inspirator mixers and the like, do not mix the gas and air sufficient to obtain proper burning. Since natural gas is more and more supplanting the use of manufactured gas, the need for an inexpensive gas-air mixer which will intimately mix the two gaseous substances sucient to obtain proper burning is especially acute.

Accordingly, it is an object of the present invention to provide an inexpensive gas-air mixer which will function to intimately mix the gas and air so as to obtain proper burning thereof.

Another object of the present invention is the provision f an improved gas-air mixing device capable of mixing gas and air as intimately as does a pre-mixer, but yet is as economical to manufacture `as the less effective venturi-type inspirator mixers.

A still further object of the present invention is the provision of a novel device for mixing two gaseous substances of materials which employs the principle of the fan to create a negative pressure to cause inspiration of one of the gaseous substances and turbulence to cause intimate intermixing of the two.

A still further object of the present invention is the provision of a novel gas-air mixer which is simple in construction, efficient in operation, and economical to manufacture and maintain.

These and other objects of the present invention will become more apparent during the course of the following detailed description and appended claim.

e invention may best be understood with reference to the accompanying drawings wherein an illustrative embodiment is shown.

In the drawings:

Figure l is a vertical sectional View of a gas-air mixing device embodying the principles of the present invention;

Figure 2 is a cross-sectional View taken along the line 242 of Figure 1;

Figure 3 is a cross-sectional view taken along the line 3 3 of Figure 1;

Figure 4 is a side elevational view of the lirst fan providing part of the device; and

Figure 5 is a side elevational view of the second fan providing part of the device.

Referring now more particularly to the drawings, there is shown in Figure l a gas-air mixing device, generally designated 10, embodying the principles of the present invention. The device ycomprises a main hollow body or ice pipe 12 having a suitable fitting 14- threadedly engaged within the forward end thereof for connection to a suitable burner, superheater or the like (not shown).

Extending longitudinally within the pipe 12 through the opposite end thereof is a tube 16 for supplying air under any pressure to the interior of the pipe. The tube 16 may be secured to the pipe 12 in any desired manner, however, as shown, a short tubular tting 18 is preferably employed which has its forward end threadedly engaged within the rearward edge of the pipe and its rearward end internally threaded for the reception of the tube 16. The tube 16 is provided with an externally threaded section 2G on its rearward portion for cooperatively engaging within the internally threaded rearward end of fitting 18. A suitable source of air under any desired pressure is supplied to the tube 16 by a suitably connected conduit Y blades are preferably struck from the metal of the tube by longitudinally cutting the same and then bending one longitudinal edge inwardly. As shown, three such blades `are provided which impart a counterclockwise rotation to the air issuing from the tube, as viewed in Figure 2.

The fitting 1S may include a T-connection 28 through which a suitable source of gas is supplied into the interior of the pipe 12. Preferably, the gas is supplied to the T-connection 25 by a suitably connected conduit 30 having a control valve 32 and a conventional zero regulator 34 therein, such as is schematically illustrated in Figure l.

Disposed within the hollow body or pipe 12 in surrounding `relationship to the forward end of the tube 16 is a relatively short tubular element 36 having the outer periphery of its rear end suitably secured to the interior periphery of the pipe. The forward end -of the tubular element 36 is provided with fan blades 38 preferably constructed in a manner similar to the blades 26. However, as shown in Figure 2, four such blades are struck from the end of the element and each is bent inwardly at a longitudinal edge so as to impart a clockwise rotation t0 the gaseous materials passing therethrough.

In the operation of the device, air is supplied at any desired pressure through tube 16. As the air issues from the end of the tube the fan blades 26direct the air outwardly toward the interior periphery of the pipe 12 and impart a rotary motion to the air. This rotary motion produces a high pressure on the periphery of the blades and a relative negative pressure at the center of the blades. ln addition, a slight venturi effect is caused by the constriction of the tube 16 where the tube end is bent to form the fan blades. This venturi effect aids in the production of the negative pressure. The negative pressure thus created in the area within the body surrounding tube 16 rearwardly of the forward end thereof, acts to inspirate the gas and the rotary motion of the air starts mixing the air with the gas.

The supply of gas is controlled by the zero regulator 34 and valve 32 acting in series. The correct amount of gas is first-set by the valve 32 and then any change in the air setting, by air valve 24, will automatically inspirate the correct amount of gas. While this arrangement is greatly preferred, it is possible to provide only a valve in the gas conduit and to control both air and gas manually.

The gas from conduit 3i) enters the pipe 12 through T-connection 28 and the fact that the gas is able to enter at the negative or low pressure center of the fan allows the gas and air to join before the fan blades 26 are reached. The gas and air are then rotated together, causing good mixing to occur before the second fan blades 38 are reached; The blades` 33 then direct the rotating mixture in ,an opposite direction so, ras to impart an opposite rotary motion thereto to complete the job of in-V timately interrnixing the gas and air.

ltcan thus 'ne seen that there hasjbeen provided a gasainrnixing devicewhich employs the principle oi the fan to create a negative pressure to cause inspiration of the gas and turbulence to cause mixing of the air; andV gas. Thus, the device of the present invention utilizes the negative pressure created to do the work of inspirating the gas. When a gas Zero regu ator is employe l, the device is capable ofV automatically proportioning the correct `amount ofV gas for any amountor" Iair f ed. Moreover, it will be notedY that the construction of the device is of suchY simplicity that it readily lends itself to economical manufacturing techniques. No moving parts are required and the relatively few number of parts employed may be easily fabricated by conventional methods.

The miser of the pr Hent invention has been tested on many of the natural Vgas, 'burners that are recommended for use with pre-mixers only, Vand the results have been successful in every instance. in some instances, better results were obtained. T he mixer is operable under many conditions and mixes equally as well with low pressure air as high pressure air. VAny type of control may be used to regulate both Vair and gas, and this ilexibility makes the, mixer applicable to systems where specialized eci nent is normally required. For example, the mixer serves very wellY as a superbi-:at burner.

it, will be understood that the form of the invention shown and described herein is to be taken as the preferred embodiment of the same and that various changes may be made within the spirit of the invention and the scope of the appended claim.

4 I claim: f ,A device. for.. mixing two gaseous. materials. Comprising a hollowV body/,a tube having an end disposed jkwithin said hollow body for supplying one of said gaseous mal terrials into the interior thereof, said tube end having fan blades struck therefromV forV directing thev ilow of ithe one gaseous material issuing therefrom ou wardlyr towardV vand, said tubular element yhaving an end extending forwardly of said tube end, the forwardly extending end of s aid tubular element having fan blades struck therefrom for directing the mixed gaseous materials in' a rotary motion in the opposite direction to intimately intermix the two.

References Cited in the Vfile of this patent UNITED STATES PATENTS 1,194,740 Hunter Aug. l5, 1916 27,270,015 June 18, 1918 2,216,846V Lewis Oct. 8, 1940 2,293,632 Sauer Aug. 18, 1942 

